The invention relates to a method for detection and location of a difference in density and/or structure and/or chemical composition of a biological tissue (7) which is subjected to continuous illumination in a first determined band of frequencies, causing the former to generate a phenomenon of fluorescence, autofluorescence or luminescence in a second band of frequencies. Said method is characterized in that it comprises the following stages: the biological tissue thus illuminated is visually captured by colour video means provided with image sensors with a mosaic of pixels provided with additional colour filters; for each image point thus obtained 1) information relating to the energy received by each pixel is collected in order to reconstitute an image of the biological tissue (7), b) amplification occurs for the signal corresponding to the energy received in the second frequency band in order to characterize the biological tissue (7) difference or to cause the image thus obtained to appear.